The Viper Resource Center (VRC), P40 competitive renewal, at Texas A&M University-Kingsville proposes to continue the aims of the initial grant application. The resources will be expanded and snake venom, venom fractions, blood and cells will be made available to the biomedical research community. The research segment of the proposal will focus on improving the products by characterizing important molecules found in venom for biomedical research. Because of university support and NIH funding, the VRC within the Natural Toxins Research Center (NTRC) has developed a unique facility with the state-of-the-art instrumentation. There are 300 different species of venomous snakes in the world and venoms are complex mixtures of thousands of molecules. Many venomous snakes use their venoms for capturing prey by interfering with the clotting cascade, which causes the animal to bleed to death. These same molecules could have therapeutic value for preventing heart attacks and strokes. A good example of these molecules is the disintegrins, which are competitive inhibitors of fibrinogen and interfere with platelet function. Disintegrins block cell-to-cell, cell-to-matrix interactions and signal transduction, thereby affecting the internal and external cellular activities of many different cells. It is our hypothesis that snake venoms are abundant and stable sources of many molecules and once purified, characterized, and cloned, could have many potential applications in medicine. Based on this hypothesis, the specific aims are to continue: (1) increasing the number of venomous snakes at the VRC for biomedical use;(2) characterizing snake venoms by high performance liquid chromatography and various assays to determine medical applications of venom molecules;(3) improving the Internet database for better dissemination of information to investigators;and (4) using the latest techniques such as proteomics to determine the molecular weights and amino acid sequences of venom proteins. The expected results will be that investigators will have access to a wide variety of properly maintained snakes, quality venoms and characterized fractions for biomedical research. The snakes, their venoms and venom fractions are placed on the NTRC Internet database, which can be queried. Venom can be ordered at a later date from the same snake, since all snakes have pit tags. Evaluation of the VRC will be based on the number of investigators using the venoms, publications, and information disseminated through the Internet database. The significance of the proposed research is that venom molecules have important biomedical applications in many different areas such as strokes, heart attacks, cancer and other medical problems.